Conventionally, such a technology as described in Patent Document 1 has been existing as a syringe device and a method of preparing drugs using the device.
Patent Document 1 discloses a syringe device including: a cylindrical coupling holder (6); an intermediate holder (3); a first syringe (1) with a bottomed cylindrical shape configured to store a solvent and having an unsealably sealed distal bottom portion; a second syringe (2) with a bottomed cylindrical shape configured to store a dissolvable drug and having an unsealably sealed distal bottom portion; and a double-ended needle assembly (10).
In the syringe device disclosed in Patent Document 1, as a first step, the distal bottom portion of the first syringe (1) is unsealed with one needle point (55b) of a double-ended needle assembly (10) by inserting and pushing a push rod (15) into the first syringe (1). At this time, the intermediate holder (3) is locked by locking means at a stand-by position, where the double-ended needle assembly (10) at an initial position is not affected. Subsequently, as a second step, the intermediate holder (3) is unlocked and the intermediate holder (3), being in the first cylindrical portion (11), is then pushed toward a partition wall (31) so that the double-ended needle assembly (10) is pushed to move to a second position, and the distal bottom portion of the second syringe (2) is unsealed by other needle point (55a) of the double-ended needle assembly (10). The push rods (15, 16) inserted into the respective syringes (1, 2) are pushed alternately in a state in which the both syringes (1, 2) are in communication with each other via the double-ended needle assembly (10), whereby the solvent gets mixed with and dissolves the drug to produce a liquid medication.
In this manner, in Patent Document 1, the distal bottom portions of the first and second syringes is unsealed by both needle points of the double-ended needle assembly (10) by a two-step pushing operation, and during the two-step operation, another operation is required for unlocking the intermediate holder.
In general, in a device configured to prepare a mixed solution by using a drug filled container and a solvent filled container, the drug filled container is held in a decompressed state in terms of stability of a drug and a sealing performance of the container in many cases, and a double-ended needle is generally used for communicating the mixed solution to each other between the two containers.
However, the technical field of the device as described above has a common drawback as follows. In other words, when one of needle points of the double-ended needle penetrates through a rubber packing or a rubber plug of the drug filled container before the solvent filled container is penetrated, entry of air from the other needle point of the double-ended needle into the decompressed rubber packing is likely to occur. In this manner, when air flows into the drug filled container, this may cause oxidation, decomposition, and transformation of effective components, as well as remarkable increase in volume of the prepared liquid medication, which may hinder adequate administration. In contrast, when the one of the needle points of the double-ended needle penetrates through the solvent filled container first, liquid leakage may occur through the other needle point of the double-ended needle from the container.